Dishwasher door counterbalancing apparatus



April 26, 1966 ULLMAN, JR, ET AL 3,248,161

DISHWASHER DOOR COUNTERBALANCING APPARATUS Filed Dec. 11, 1965 3 Sheets-Sheet 1 FlG.l

INVENTORS MYRON E. ULLMAN JR. a

JERRY M. HARROFF 3 Sheets-Sheet 2 M. E. ULLMAN, JR, ETAL DISHWASHER DOOR COUNTERBALANCING APPARATUS April 26, 1966 Filed Dec. 11 1963 MN ww mm mm mm o o N9 N 9n 9 mm m ow J N 0P, H 8 5 mm 5 ORNEYS April 26, 1966 v ULLMAN, JR" ET AL 3,248,161

DISHWASHER DOOR COUNTERBALANCING APPARATUS Filed Dec. ll, 1965 3 Sheets-Sheet 5 l INVENTORS I 1 MYRON E. ULLMAN JR. 8 88 76 BY JERRY M. HARROFF FIG.8 82 72 United States Patent F 3,248,161 DISHWASHER DOOR COUNTERBALANCING APPARATUS Myron E. Ullman, Jr., Canfield, and Jerry M. Harroif,

Salem, Ohio, assignors to Mullins Manufacturing Corporation, Columbiana, Ohio, a corporation of Ohio Filed Dec. 11, 1963, Ser. No. 329,652 8 Claims. (Cl. 312319) The present invention concerns an improvement for a dishwashing machine and, more particularly, to an apparatus for counterbalancing the door of the machine.

In various types of domestic applicances such as ovens, and washing machines for example, access is gained to the working chamber by means of a pivotally mounted door which when closed forms one of the sides of the machine. Since these doors are often insulated and made of metal they are quite heavy, and are therefore, for the convenience of the user, usually counterbalanced so as to enable them to be more easily opened and closed.

However the various counterbalancing arrangements now in use for such doors leave something to be desired from such standpoints as economy of manufacture, simplicity of constructionfor purposes of installation and repair, and effectiveness of the counterbalancing achieved. Therefore, foremost among the objects of this invention is that of providing a counterbalancing apparatus which constitutes a significant improvement over the prior apparatus from each of the standpoints noted above.

A particularly significant shortcoming in many of the counterbalancing arrangements employed at present is the inability of these arrangements to support the door in many of the open door positions which lie between the fully opened and closed positions. Thus, for example, in many counterbalancing constructions as the door approaches the closed position it will suddenly slam shut. This is a distinct disadvantage which this'invention has as one of its further objects to overcome by providing a counterbalancing apparatus which will enable a door to be suspended in the infinite number of positions which lie between the fully opened and closed positions.

Briefly stated the present invention, which achieves the foregoing objects and others, comprises a pair of bearing blocks and attached coil springs which are mounted adjacent the opposite side edges on the front of the door to be suspended. Connected to each of the coil springs is a cable which extends toward and around the opposite bearing block and is secured to the side wall of the ap pliance. As the door is drawn open from the closed position the coil springs expand and the cables slide around and through the bearing blocks.

In view of the foregoing it is a still further object of this invention to provide an apparatus for counterbalancing doors indishwashing machines and the like.

The novel features that are considered characteristic of the invention are set forth in the appended claim-s. However the invention itself, both as to its organization and operation, together with additional objects and advantages thereof, will best be understood from the following description of a specific embodiment when read in conjunction with the acompanying drawings in which:

FIG. 1 is a :front elevational view of an automatic dishwasher with parts of the exterior housing broken away to illustrate the location of the counterbalancing apparatus of the invention therein;

FIG. 2 is a sectional view taken along the arrowed line 22 of FIG. 1;

FIG. 3 is a front elevational view of the apparatus shown in FIG. 2;

FIG. 4 is an enlarged view of the details shown on the right hand side of FIG. 2;

ice

FIG. 5 is a side elevation .of a portion of the dishwashing machine shown in FIG. 1, with parts broken away and with other parts shown in broken lines to illustrate the structural arrangement and operation of the invention when the door is in two of its opened positions and in its closed position;

FIG. 6 is a detailed view in section of the construction shown in the lower right hand corner of FIG. 5; and

FIGS. 7 and 8 are perspective views of the bearing block which forms a part of the apparatus of the present invention.

While the various features of this invention are hereinafter illustrated and described as being particularly adaptable to provide a counterbalancing means for a dishwasher or the like, it is to be understood that the various features of this invention can be utilized singly or in any combination thereof to provide a counterbalancing means for other devices as desired.

Therefore, this invention is not to be limited to the only embodiment illustrated in the drawings, because the drawings are merely utilized to illustrate one of the wide variety of uses for this invention.

Referring now to FIGS, 1, 2 and 5 of the drawings, the dishwasher is designated generally by the numeral 10 and consists of a housing 12 which includes opposite side walls 14 and 16 having flanges 18 and 20 respectively formed along their forward edge portions. The dishwasher 10 is provided at the front thereof with a doorway 22 through which the dishwasher may ,be loaded with dishes to be washed, rinsed and dried and through which it may be unloaded after these operations have been completed. The doorway 22 is closed by a door 24 when the dishwasher 10 is in operation, the door being hinged addevices.

.tion.

The dishwasher 10 includes various electrical elements which cooperate to carry out the washing, rinsing and drying operations mentioned. Among these electrical ele- 111611128 is a timer (not shown) which is set for sequentially controlling the aforementioned operations by means of a control knob 26 and which in the course of its operation actuates a motor 28 which drives a pump 30 for pumping water into and outof the machine during the washing and rinsing operations.

With reference now to FIGS. 1-4, the counterbalancing apparatus of the present invention generally consists of a pair of bearing blocks 32, 34 mounted adjacent the side edges of door 24, a pair of coil springs 36, 38 attached to bearing blocks 32, 34 respectively and extending across the front face of door 24, and a pair of cables 40, 42 attached to coilsprings 36, 38 respectively which bear against and around blocks 34, 32 and are secured at their opposite ends to flanges 20, 18.

With reference now to the specific details of construction, the apparatus of the present invention is so constructed that it may be mounted in position on door 24 without using nuts, bolts, 'or other standard retaining For the most part this is achieved by forming the. side edges of the inner wall 48 of door 24 and bearing blocks 32 and 34 in such a manner that the blocks may be simply and quickly pressed into locked engagement with the inner wall of the door.

In order to accomplish this, inner door wall 48 which is generally flat in its central portion 50 is progressively provided, see FIGS. 2 and 3, from its central portion to its opposite side edges with rearwardly projecting channels 52, 54, rounded shoulders 56, 57, flat strips 58, 59 and forwardly projecting flanges 60, 62.

The bearing blocks 32 and 34 which are formed along one side to be pressed into engagement with the undulated front surface of wall 48, are identical in form as shown in FIGS. 7 and 8 and are preferably made of a thermo plastic material having suflicient mechanical properties to withstand the stresses imposed during the operation of the counterbalancing structure of the present invention. Since bearing blocks 32, 34 are identicalin all respects, reference will be made only to block 32 in the course of describing the specific structural features and form of the blocks.

As best shown in FIG. 7, block 32 is provided with a hook portion 64 projecting upwardly from one corner of top surface 66 adjacent front surface 68 the hook finger 70 of which points toward opposite end portion 72 of the block. Front surface 68 which includes a side of hook portion 64 is provided with a longitudinal groove 7 74 spaced below hook portion 64 and extends the length of block 32 from end portion 78 up to end wall 76 of opposite end portion 72. End portion 72 which has the general form of a rectangular box is provided with an aperture 80 which extends from its fiat back surface 82 into the side groove 74 adjacent end wall 76. Since aperture 80 and groove 74 are formed for the purpose of receiving either cable 40 or 42 in sliding engagement therewith, the opposite end walls adjacent aperture 80 are formed to flare outwardly at surface 82 (see FIG. 8), and to curve toward end 78 at groove 74 (see FIG. 4).

Referring now to FIGS. 4 and 8, rear surface 84 of block 32 is formed to fit into and engage the undulations provided adjacent the opposite side edges in the face of inner door wall 48. In order to achieve this, rear surface 84 is formed with a central projecting portion 86 intermediate opposite end walls 72 and 78 which portion is provided on its opposite sides with a pair of rearwardly extending legs 88 and 90.

Since the function of projecting portion 86 is to fit into either channel 52 or 54 and engage the side walls thereof for the purpose of securingbearing block 32 to inner door wall 48, the width of portion 86 is slightly larger than the width of either channels 52 or 54 thereby assuring a tight forced fit engagement between portion 86 and the channel into which it is pressed.

Additional support is also provided block 32 in its mounted position on inner door wall 48 when curved rear surface shoulder 92, flat back surface 82 and flat end 72 are nested within and against similarly formed inner wall surfaces presented by rounded shoulder 56 or 57, flat strip 58 or 59, and the inner wall of flanges 60 or 62, respectively.

Since, as previously indicated, blocks 32 and 34 are of identical construction they will, as of necessity, be inverted with respect to one another when mounted in the manner indicated adjacent the opposite edges on inner wall 48 of door 24. Thus, as is best shown in FIG. 3, the position of block 32 is such that its hook portion 64 is projecting upwardly whereas the hook portion 64 on block 34 which is mounted adjacent the opposite edge of door 24 is projecting downwardly. As is apparent from FIG. 2, this reversal of parts wherebyhook portions 64 on mounted blocks 32 and 34 project in opposite directions achieves the result of enabling spring 36 and cable 40 to be mounted in spaced parallel relationship with adjacent spring 38 and cable 42. In this manner the springs and cables are in non-interfering relationship during the opening and closing of door 24.

In order to provide a continuous path for cables 40, 42 through inner wall 48 of door 24 and flanges 18 and of side walls 14 and 16 respectively, apertures 94 and 96 are provided in flat strips 58 and 59 respectively, and apertures 98 and 100 are provided in flanges 18 and 20 respectively, all of which apertures are in horizontal alignment with block apertures 80 when door 24 is in its closed position as shown in FIG. 2.

Cables 40 and 42, as used in the illustrative embodiment of the present invention, are preferably formed with a steel cable core or other material that will not cold flow 4: under tension. Furthermore, in order that cables 40 and 42 may slide smoothly along and through groove 74 and aperture without causing any appreciable wear to either surface, the steel cable core is encased in a nylon coating or sleeve throughout its length. In order that cables 40 and 42 may be attached to coil springs 36 and 38 respectively, one end of each cable is provided with a hook eye 102 which may be crimped thereon. In addition, a cylindrical stop member 104 is attached as by crimping also to each of cables 40 and 42 adjacent hook eye 102, the diameter of which member 104 is slightly greater than the width of grooves 74 in blocks 32 and 34 so as to prevent further movement of cables 40, 42 through grooves 74 when member 104 engages side 78 of ,blocks 32 and 34.

As best shown in FIG. 3, springs 36, 38, and cables 40, 42 are mounted in position for providing counterbalancing support for door 24, by hooking one end of springs 36 and 38 on to hook portion 64 of blocks 32 and 34 respectively and the opposite ends of springs 36, 38 through eye portions 102 of cables 40 and 42 respectively. With door 24 in its closed position against doorway 22, the unattached end of cable 40 is then inserted into aperture 80 of block 34 and through aperture 96 in flat strip 59, and aperture in flange 20 of side wall 16. Also, the unattached end of cable 42 is likewise inserted into aperture 80 of block 32 and through aperture 94 in fiat strip 58, and aperture 98 in flange 18 of side wall 14. The unattached ends of cables 42 and 40 may be retained against withdrawal from apertures 98, 100 in flanges 14, 16 respectively, by means of cylindrical stop members 106 which may be crimped thereon. Furthermore in order to protect nylon coated cables 40, 42 from abrasive contact with the edges of apertures 98, 100, and also in order to prevent members 106 from passing through apertures 98 and 100, cable retainers 107 having a centrally projecting apertured portion 109 may be inserted onto cables 40, 42 and positioned between member 106 and the apertured flanges as best shown in FIG. 4 of the drawings.

With the ends of cables 40, 42 secured against flanges 20, 18 respectively, in the manner described, and with door 24 in its fully opened horizontal position, the elongation of coil springs 36, 38 and the position of stop members 104 on cables 40, 42 should be such that stop members 104 on cables 40, 42 are in abutment with ends 78 of blocks 34 and 32 respectively as best shown by the broken line portions in FIG. 2. In other words when door 24 is in its fully opened horizontal position, it is supported against further downward movement by stop members 104 and not by springs 36, 38. In this connection the lengths of cables 40 and 42 are preferably such that they extend, when door 24 is fully opened, from their secured position in flanges 20 and 18 around blocks 32 and 32 and slightly beyond block ends 78 where eyelet portions 102 and stop members 104 are mounted thereon.

Referring now to FIGS. 5 and 6, as door 24 is opened from its closed position against doorway 22, the angle of wrap, that is the arc of engagement between cables 40, 42 and the flared surface portion of aperture 80 is increased as the door approaches its fully opened horizontal position. This increase in the angle of wrap is an important factor in the ability of the apparatus of this invention to support door 24 in any of its infinite number of opened positions.

The foregoing description of the counterbalancing apparatus of the present invention is an exemplary embodiment for purposes of illustration, and as such it should be understood that various changes, modifications and substitutions may be made in connection with some or all of the elements of the combination which comprises the invention without departing from the spirit of the invention as defined by the claims which follow.

We claim:

1. In a dishwashing machine having a housing structure including opposite side walls, a doorway and a door pivotally mounted to said structure and movable relative to said housing between various opened positions and a closed position closing said doorway, a door counterbalancing mechanism comprising: a pair of bearing blocks mounted on the front of said door adjacent the opposite side edges thereof; a pair of coil springs each connected at. one end to a bearing block and extending toward each other across the front of said door; and a pair of cables each connected at one end to the unattached end of said springs and engaged in sliding contact against and around said blocks and attached at the other end to the side walls on opposite sides of the door whereby said door is supported in its various opened positions.

2. The dishwashing machine set forth in claim 1, in which each of said bearing blocks are formed with a continuous path for receiving a cable therein in sliding engagement therewith.

3. The dishwashing machine set forth in claim 1, wherein said cables are encased within a plastic coating and provided with stop means on at least one of said cables for preventing further movement in one of the opened positions.

4. The dishwashing machine set forth in claim 3, Wherein said stop means are formed on said cable adjacent the end thereof attached to one of said coil springs for preventing movement of said cable through said bearing means.

5; The dishwashing machine set forth in claim 1, wherein each of said bearing blocks is provided with a hook portion for engaging an end of said coil spring.

6. The dishwashing machine set forth in claim 2, wherein the continuous path formed in said bearing block comprises an open groove portion and an aperture portion formed therethrough.

7. In the combination of a housing structure including side walls, a doorway having spaced sides, a door pivotally mounted with respect to said housing and said doorway and movable between an open position and a closed position closing said doorway, and a counterbalancing mechanism for said pivotally mounted door, the improvement comprising: said counterbalancing mechanism including a flexible, elongated member having two end portions, means for attaching one of said end portions onto said door and adjacent one side of said doorway, means for attaching the other of said end portions onto said housing and adjacent the other side of said doorway, a bearing block secured onto said door adjacent said other side of said doorway, said elongated member extending across said door and around said bearing block, said bearing block having a surface frictionally engaging said member whereby said surface restrains movement of said member along said surface to hold said member in an infinite variety of adjusted positions on said bearing block, and said elongated member including an elastic, expandable section intermediate said doorway sides to urge said door toward the closed position.

8. The improvement as defined in claim 7 wherein said frictionally engaging surface includes an elongated groove in said bearing block for receiving said flexible, elongated member extending around said bearing block.

References Cited by the Examiner UNITED STATES PATENTS 1,640,250 8/ 1927 Possons. 2,833,270 5/1958 Brown et a1. 126l91 2,921,575 1/1960 Fry 126191 3,049,115 8/1962 Carnahan et a1. 126-191 CLAUDE A. LE ROY, Primary Examiner.

FRANK B. SHERRY, Examiner.

F. DOMOTOR, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N06 3, 248, 161 April 26, 1966 Myron E, Ullman, Jr,, et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

In the grant, lines 2 and 3, for "assignors to Mullins Manufacturing Corporation, of Columbiana, Ohio, a corporation of Ohio," read assignors to Mullins Manufacturing Corporation, of Salem, Ohio, a corporation of Delaware, in the heading to the printed specification, lines 5 and 6, for "assignors to Mullins Manufacturing Corporation, Columbiana, Ohio, a corporation of Ohio" read assignors to Mullins Manufacturing Corporation, Salem, Ohio, a corporation of Delaware 0 Signed and sealed this 28th day of November 1967,

(SEAL) Attest:

Edward M. Fletcher, Jr. EDWARD J. BRENNER Attesting Officer Commissioner of Patents 

7. IN THE COMBINATION OF A HOUSING STRUCTURE INCLUDING SIDE WALLS, A DOOWARY HAVING SPACED SIDES, A DOOR PIVOTALLY MOUNTED WITH RESPECT TO SAID HOUSING AND SAID DOORWAY AND MOVABLE BETWEEN AN OPEN POSITION AND A CLOSED POSITION CLOSING SAID DOORWAY, AND A COUNTERBALANCING MECHANISM FOR SAID PIVOTALLY MOUNTED DOOR, THE IMPROVEMENT COMPRISING: SAID COUNTERBALANCING MECHANISM INCLUDING A FLEXIBLE, ELONGATED MEMBER HAVING TWO END PORTIONS MEANS FOR ATTACHING ONE OF SAID END PORTIONS INTO SAID DOOR AND ADJACENT ONE SIDE OF SAID DOORWAY, MEANS FOR ATTACHING THE OTHER OF SAID END PORTIONS ONTO SAID HOUSING AND ADJACENT THE OTHER SIDE OF SAID DOORWAY, A BEARING BLOCK SECURED ONTO SAID DOOR ADJACENT SAID OTHER SIDE OF SAID DOORWAY, SAID ELONGATED MEMBER EXTENDING ACROSS SAID DOOR AND AROUND SAID BEARING BLOCK, SAID BEARING BLOCK HAVING A SURFACE FRCTIONALLY ENGAGING SAID MEMBER WHEREBY SAID SURFACE RESTRAINS MOVEMENT OF SAID MEMBER ALONG SAID SURFACE TO HOLD SAID MEMBER IN AN INFINITE VARIETY OF ADJUSTED POSITIONS ON SAID BEARING BLOCK, AND SAID ELONGATED MEMEBR INCLUDING AN ELASTIC, EXPANDABLE SECTION INTERMEDIATE SAID DOORWAY SIDES TO URGE SAID DOOR TOWARD THE CLOSED POSITION. 